From what I gathered, Nyx is known in pretty much every polytheistic religion, where she stands in as the mother/creator goddess. This includes Cherokee mythology (also, for some reason, she's known as both Nyx and Gaea, even though BOTH WHERE GREEK GODDESSES! >_<). The vampires know her as Nyx, because their ancestors (who apparently were all from Greece because yeah, vampires certainly weren't from anywhere else in the ancient world I'm sure) looked to the Goddess of Night as their patron goddess and protector. From then on, all vampires worship Nyx. I have no idea if they know that she is present under other names in other religions because as far as I can tell, Zoey Redbird is the only character to meet Nyx face-to-face thus far.

I have no idea how Kalona (the fallen angel) fits in. I *think* there's the "all myths are true" thing, where the various religious figures spill over into one big thing, but that still doesn't make sense. If fallen angels are real, doesn't that mean the Judeo/Christian God and Jesus are real? What about non-fallen angels? (Granted I haven't actually reached that part yet so it *could* be explained, but given this book's track record, I doubt it) What about the Cherokee spirits/deities besides the one Nyx represents? What about the other Greek gods and goddesses? We're told that Nyx's son is Eros, who was most definitely immortal. Where did HE go?